Galaxy Zoo 2: meet the mergers

Today saw the launch of Galaxy Zoo 2: the project that enables web users to contribute to research into galaxies and how they evolve.

This report from BBC Breakfast's Graham Satchell gives an excellent overview of the project and includes an interview with one of Galaxy Zoo's founders, Oxford's Chris Lintott as well as just a few of the galaxy-spotting volunteers [nicknamed 'Zooites'] who have helped make the project such a success.

First reports are that GZ2's servers are buzzing with ten times the traffic of the original GZ launch: no doubt helped by the fact that Graham's report is linked from the front page of the entire BBC website! Chris's appearance on The Today Programme this morning can't have hurt either. 

Galactic mergers - cosmic 'train wrecks' in which galaxies collide - are one of the things that the GZ2 team hope users visiting the site can help them describe in detail. One of the discussions we had whilst putting the release together was whether mergers could be described as 'odd' or 'unusual' - although there was agreement that they are rare. 

Interestingly, as part of looking into this, I stumbled across this New Scientist piece that reports on research into how, in less than two billion years, our own galaxy - the Milky Way - will in fact merge with our neighbour the Andromeda galaxy: these two galaxies are currently rushing towards each other at 120 kilometres per second.

New Scientist's Hazel Muir writes: 'The scientists watched how gravity choreographed the motions of the two galaxies up to 10 billion years into the future. The results suggest they will pass close to each other in less than 2 billion years, well within the Sun's lifetime. At this point, their mutual gravity would start to mess up their structures and tug out long tails of stars and gas.'

'The two galaxies would then overshoot and come together again for a second close passage before finally merging about 5 billion years from now. The merged galaxy, which [the researcher] dubs Milkomeda, will be a blobby elliptical galaxy, rather than a neat spiral like Andromeda or the Milky Way today.'

Perhaps we should all visit GZ2 to find out what a merger looks like, just in case we're around in two billion years' time to watch...